How our microbes can influence who we're attracted to

While a certain kind of romantic chemistry has long been thought to be crucial for relationships, more evidence is starting to support the notion that having the right microorganisms may be important.

Scientists for years have been investigating the vast role that our microbiomes—a population of microorganisms estimated to hold more than 10 times as many cells as our actual bodies—play in determining such key traits as our immunological makeup.

But one scientist proposes that microbes can also have a direct effect on human sexual attraction.

“In order to understand humans, and to better serve humans through better medicine, we have to learn how we have become the creatures that we are—vast collaborations of co-dependent and co-linked and cooperative cells.”

Miller said that kissing partners tend to have similar microbes in their mouths. Those microorganisms were apparent regardless of kissing frequency, meaning it might be possible that those with similar oral microbial composition are drawn to one another.

Miller said other evidence suggests sexual attraction is also based on immunological status, with individuals drawn to those with a complementary immunological makeup so as to broaden their offspring's spectrum of immunity.

The combination of those two factors helps to influence the way humans select sexual partners and can determine what we find attractive in one another, Miller said.